28364981 has 4 divisors (see below), whose sum is σ = 28555500. Its totient is φ = 28174464.

The previous prime is 28364971. The next prime is 28365019. The reversal of 28364981 is 18946382.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 970225 + 27394756 = 985^2 + 5234^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28364981 is a prime.

It is a super-2 number, since 2×28364981² = 1609144294260722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28364971) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 95036 + ... + 95333.

It is an arithmetic number, because the mean of its divisors is an integer number (7138875).

Almost surely, 2^28364981 is an apocalyptic number.

It is an amenable number.

28364981 is a deficient number, since it is larger than the sum of its proper divisors (190519).

28364981 is a wasteful number, since it uses less digits than its factorization.

28364981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190518.

The product of its digits is 82944, while the sum is 41.

The square root of 28364981 is about 5325.8784251990. The cubic root of 28364981 is about 304.9726070534.

The spelling of 28364981 in words is "twenty-eight million, three hundred sixty-four thousand, nine hundred eighty-one".